ICM_DECOMPRESSEX_BEGIN

The ICM_DECOMPRESSEX_BEGIN message notifies a video compression driver to
prepare to decompress data.

ICM_DECOMPRESSEX_BEGIN

wParam = (DWORD) (LPVOID) &icdex;

lParam = sizeof(ICDECOMPRESSEX);

Parameters

icdex

Address of a ICDECOMPRESSEX structure containing the input and output formats.

lParam

Size, in bytes, of ICDECOMPRESSEX.

Return Values

Returns ICERR_OK if the specified decompression is supported or
ICERR_BADFORMAT otherwise.

Remarks

When the driver receives this message, it should allocate buffers and do any
time-consuming operations so that it can process ICM_DECOMPRESSEX messages efficiently.

If you want the driver to decompress data directly to the screen, send the
ICM_DRAW_BEGIN message.

The ICM_DECOMPRESSEX_BEGIN and ICM_DECOMPRESSEX_END messages do not nest. If
your driver receives ICM_DECOMPRESSEX_BEGIN before decompression is stopped with
ICM_DECOMPRESSEX_END, it should restart decompression with new parameters.